Natural Attenuation of Groundwater Contaminants: New Paradigms, Technologies, and Applications

Go to Course: https://www.coursera.org/learn/natural-attenuation-of-groundwater-contaminants

Introduction

### Course Review: Natural Attenuation of Groundwater Contaminants: New Paradigms, Technologies, and Applications The environmental challenges associated with groundwater contamination are multifaceted and growing more complex as industrial activities expand and urbanization increases. Addressing these issues requires innovative approaches, and the course **Natural Attenuation of Groundwater Contaminants: New Paradigms, Technologies, and Applications** on Coursera does an exemplary job of bridging theory and practice for professionals in the field. #### Course Overview This comprehensive course delves into monitored natural attenuation (MNA) as a viable remediation method, providing participants with an in-depth understanding of both traditional methodologies and cutting-edge technologies developed over the past decade. This focus on MNA offers a fresh perspective on when and where to apply natural attenuation processes, making it essential for environmental engineers, hydrogeologists, and policymakers alike. The course is structured in a user-friendly format with clear navigation, ensuring an accessible learning experience. It takes participants through the historical context of groundwater remediation, effectively setting the stage for discussions on MNA's evolution, alongside the latest advancements in understanding key attenuation processes. #### Syllabus and Key Topics The syllabus is both broad and detailed, capturing essential aspects of groundwater remediation: 1. **Course Overview and MNA as an Evolving Technology**: - An introduction to the history of groundwater remediation, including critical protocols from 1994 to 2015. 2. **Biodegradation Principles**: - Detailed discussions on conditions conducive to biodegradation, illuminating when these natural processes can effectively remediate contaminants. 3. **Abiotic Degradation Principles**: - Exploration of abiotic processes, emphasizing key chemical reactions and minerals involved, along with methods for assessing their relevance at specific sites. 4. **Attenuation and Storage in Low K Zones**: - Investigating how contaminants are stored in geological media and the mechanics of diffusion and back diffusion, supported by case studies. 5. **Dilution as an Attenuation Process**: - Examination of scenarios where dilution serves as an attenuation mechanism, alongside principles of groundwater flow. 6. **Better Technologies**: - Overview of innovative methods for proving biological degradation, including compound-specific isotope analysis that aids in understanding attenuation rates and pathways. 7. **Monitoring for MNA**: - Strategies for effective monitoring to support MNA initiatives, including data collection and long-term performance assessments. 8. **Modeling Tools to Support MNA**: - Introduction to analytical and numerical models that assist in projecting remediation timelines and plume dynamics. 9. **New Directions for MNA**: - A look at emerging tools and developments in various contaminant classes and methodologies, concluding with insights from industry experts. #### Recommendations This course excels in bringing together theory, cutting-edge technologies, and real-world applications in groundwater management. The combination of comprehensive lectures and practical case studies provides both novices and experienced professionals in environmental science and remediation industries with a valuable learning platform. If you are passionate about environmental remediation, particularly the dynamic field of groundwater cleanup, I highly recommend enrolling in this course. It not only enhances your understanding of MNA but also equips you with the knowledge to implement these methods in real-world scenarios effectively. Overall, this course is an investment in both learning and professional development, and it is poised to significantly impact how practitioners approach groundwater contamination challenges in our ever-evolving environmental landscape.

Syllabus

Course Overview and MNA as an Evolving Technology

Welcome to the course! In the Course Overview section, you will find general information about the course as well as instructions on how to navigate the course. In the lectures for this week, we will start with history. We look at a general brief history of groundwater remediation, and then a specific history of MNA featuring a list of the key protocols from 1994 to 2015. Special topics include active remediation vs. MNA, and Neat New MNA Technologies, and how degradation, storage, and dilution are all part of the MNA story.

In this series of lectures, we will learn when biodegradation can or cannot occur and what conditions are conducive to faster degradation.

In this series of lectures, we will focus on the principles of abiotic degradation and discuss how these processes support monitored natural attenuation. You will be learning about the key reactions and minerals that are involved in abiotic degradation. We will also be covering what methods are used to determine if abiotic degradation is relevant at a particular site, and the rates at which these reactions may be occurring

In these lectures, we will focus on the idea that storage of contaminants in geologic media as a potential natural attenuation mechanism. Under this scenario, certain contaminants diffuse in low permeability media such as silt, clay, and limestone and then eventually reenter the aquifer by a process called back diffusion. Like sorption, this process is not destructive, but attenuates a contaminant plume by sequestering some of the initial loading and then slowly releases it over long time scales. You will learn about diffusion vs. dispersion, see case studies in the lab and field, learn how to sample and model this process, and hear the latest research about degradation processes associated with matrix diffusion.

In this series of lectures, we will discuss how dilution is an attenuation process – sometimes. We start with the basics, and review groundwater flow and one of the “top ten things” that every hydrogeologist should know: the distinction between Darcy Velocity and Seepage Velocity. Next we give some examples of regulatory programs where dilution is considered an acceptable attenuation process. Then we present how dispersion and mixing in wells are dilution-related processes. Finally we show how the emerging field of mass flux/ mass discharge can be used to see if a contaminant plume is strong enough to impact water supply wells and/or streams, and to see where your plume ranks in the “Plume Magnitude Classification System.”

In this series of lectures, we will focus on several established and emerging methods for demonstrating that biological and other attenuation processes are occurring. We will start with an overview on lines of evidence for biological degradation processes, and then transition to newer molecular methods for identifying and quantifying biodegradation potential for a variety of compounds. Several of this week’s lectures also examine compound-specific isotope analysis, which has been emerging as a key resource for MNA studies. You will learn how stable isotope analyses can provide critical information on whether attenuation is occurring, the rate at which it is occurring, and even the pathway that is responsible.

In this series of lectures, we will discuss how you should perform the monitoring that is such an important part of monitored natural attenuation (after all, it’s right there in the title!). We start off with a discussion of how data are collected, including using newer high-resolution techniques, to help build a proper conceptual site model and support the selection of MNA as a remedy. Then we touch on how to design a long-term monitoring program to assess the performance of MNA. Methods for analyzing concentration trends and graphically presenting MNA data are also presented, along with a discussion of the potential sources of variability in monitoring data.

In this series of lectures, we talk about models and how they can be used to understand MNA. We first start with two key MNA questions: How Long? (will the plume get) and How Far? (how long until the site is clean). Then a review of analytical computer models, remediation timeframe models, the more complex but more powerful numerical models, and even a discussion of the “Fourth Paradigm: Big Data”.

This final series of lectures will cover a mélange of interesting MNA topicsl We start with the brand new ESTCP BIOPIC tool, then talk about the broad universe of MNA that extends to a lot of different contaminant classes. Then some new developments in the LNAPL world: Natural Source Zone Depletion, both with conventional methods and a new method based on thermal monitoring. Then we talk a little bit about low threat closures and transition assessments, and end up with a brief conversation with the three instructors. And then you are done!